Pilot burner



sept. 4 1956 A. c. MUNN 2,761,497

PILOT BURNER Filed Aug. 27, 1953 Aubrey 6- Mur/n INVENTOR.

WM5/ms The present invention relates to pilot burners and moreparticularly relates to a pilot burner having a novel burner tubeconstruction to eliminate the clogging of the air inlet holes by foreignmatter such as lint and the like.

A primary object of the invention is to provide a burner tubeconstruction having an air inlet constructed in a manner to open in thepath of the combustion llame at the mouth of the burner whereby the dustand lint in the air are ignited and decomposed to purify the airtraveling through the air intake or inlet preventing clogging of the airinlet and assuring continual mixture of the primary air with thecombustion fuel.

Another very important object of the invention is the provision of apilot burner tube of the above described character that is equallyadaptable for use with either manufactured or natural gasses as well asliquiied petroleum and other similar fuels.

Yet another object of the invention, ancillary to the primary object isthe provision of a pilot burner tube wherein the primary air is admittedthrough a longitudi nal bore in the tube running parallel to the fueland air mixture outlet bore of the tube, which primary air inlet boreopens remote from the burner orice at the combustion zone of themixture.

A still further object of the invention is `to provide a primary airinlet into the burner tube which opens adjacent the combustion Zone ofthe tube and wherein a bathe is provided at the combustion zone suchthat the ame always extends across the mouth of the air inlet.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

Figure l is a side elevational view of the burner tube mounted on aburner nozzle in cross section to disclose the interior construction ofthe tube;

Figure 2 is a cross sectional View of the burner tube takensubstantially along the plane of the section line 2 2 of Figure l;

Figure 3 is a detail View of the upper end of the burner tube takensubstantially in the plane of section line 3-3 of Figure l;

Figure 4 is a cross sectional view of the deecting means at thecombustion zone of the burner tube taken substantially along the sectionline 4-4 of Figure l.

Referring to the drawings in detail, the burner tube is designated inits entirety by the numeral 10. As will be noted, this tube is of theBunsen type with certain fundamental distinctions which will becomesubsequently apparent.

The tube or body is mounted on a fuel nozzle 12 having a burner orifice14 opening into a fuel mixture outlet bore 16 having a mouth 18 openinginto the upper end of the tube. The mixture outlet bore 16 is formedwith a venturi restriction 20 in the central portion thereof StatesPatent to increase the velocity flow of the gas mixture through themixture outlet and stimulate the entrance of the primary air into thelower portion of the outlet bore to mix with the fuel.

As will be noted particularly from Figure 1, the mix: ture outlet bore16 is longitudinally offset from the axis of the tube or shell lil andis internally threaded where it opens into the lower end of the tube tofacilitate the reception of the tube on the burner nozzle 12.

The tube 10 is further formed with an air inlet or intake bore 24extending longitudinally within the tube parallel to the mixture outletbore 16 and having a mouth 26 opening into the upper end of the tube,the lower end of the bore opening into a transverse bore or passage 2Sthrough the side wall of the tube opening into the mixture outlet bore16 adjacent the burner oriiice 14.

Av suitable thumb screw 39 is threaded into the transverse passage 2Sand constitutes a valve for adjustably controlling the rate of iow ofthe primary air through the air inlet 24 to the mixture outlet 16.

The upper end of the tube 10Y is in the form of a pair of verticallyoifset steps 32 and 34 with the mouth 18 of the mixture outlet 16opening into the upper step 32 and the mouth 26 of the air inlet 24opening into the lower step 34 so that these mouths are verticallystepped and closely adjacent to one another.

A first baiile plate 36 is mounted on the step 32 and has an oricetherethrough communicating with the outlet bore 16. As will be noted inFigure 4, the plate 36 has a dat edge 38 terminating in alignment withthe vertical shoulder of the tube l@ between the steps 32 and 34. Theremaining periphery of the plate 36 projects laterally outwardly aroundthe tube 10.

A small hollow cylinder 42 is mounted on the plate 36 and communicateswith the mixture outlet bore 16. Ignition ports Mare formed transverselythrough the side walls of the cylinder and as the fuel and air mixtureleaves these ports, ignition takes place. A bathe plate 46 closes theupper end of the cylinder 42. The peripheral portion of the battle plate46 projects laterally beyond the side wall of the cylinder 42 andvertically spacedly overlies the mouth 26 of the air inlet bore 24.Thus, as the fuel and air mixture is ignited at the ignition ports 44,the resultant llame is directed laterally outwardly from the tube 10 bythe ports 44 and is baiiied to always overlie or extend across the mouth26 of the air inlet bore 2a to decompose any foreign materials whichwould tend to clog the air inlet prior to the entrance of the air intothe mouth 26 of the air inlet. With this arrangement, clogging of theprimary air inlet or inlets is eliminated.

In the past, with the Bunsen type burner tubes wherein the primary airentered through side wall openings in the tube, the air holes had atendency to close completely olf by clogging or gumming through theaction of dust and lint. When such clogging occurs, the pilot lightburns with a yellow ame and eventually goes out altogether when theclogging is complete. However, when the pilot light is connected to amagnetic valve to control -the gas supply to an appliance or the like,the yellow llame ordinarily does not produce enough heat for thetherrnocouple to produce any voltage and the magnetic valve cuts oif thegas supply to the appliance. This failure results in about S0 per centof the service calls necessitated because of a failing pilot light.Further, during the yellow ilame period, excessive carbon is producedwhich frequently necessitates cleaning of the appliance after the pilotlight burner is restored to its proper operating condition. The presentinvention eliminates this essentially troublesome failure of pilot lightburners in an inexpensive and practical manner.

From the foregoing description, the construction and operation of theinvention are believed to be readily apparent. Howevr, since numerousmodifications and changes will readily occur to those skilled in the artafter a careful consideration of the foregoing speciiication taken inconjunction with the accompanying drawing, it is not desired to limitthe invention to the exact construction shown and described, but allsuitable modifications may be resorted to which fall within the scope ofthe appended claim.

What is claimed as new is as follows:

A pilot burner comprising a vertical tubular body having upper and lowerends, a longitudinal through mixture outlet bore therein oiset to oneside of its axis and a longitudinal primary air inlet bore thereinoffset to the opposite side of its axis, said air inlet bore having aninlet mouth at the upper end of the body and a blind lower end spacedfrom'the lower end of said body, Vsaid body having a transverse boretherein communicating the blind end of said inlet bore with said outletbore, a fuel nozzle extended into said outlet bore from the lower end ofsaid body to said transverse bore for velocity discharge past saidtransverse bore to draw primary air from said inlet bore into saidoutlet bore, a rst transverse battle ,t over said mouth for burning lintand dust at said mouth,

and a second transverse bale plate surmounting said cylinder and closingthe same above said ports, said irst baffle plate being offset to oneside of said mouth to clear the same, said baille plates extendinglaterally under and over the other of said ports to battle arnelaterally therei of and said second bale plate extending over said oneaperture aligned with said outlet bore and relatively port and mouth todeect ame laterally over said mouth.

References Cited in the tile of this patent UNITED STATES PATENTS1,105,987 McSorley Aug. 4, 1914 2,360,310 Anderson Oct. 17, 1944 FOREIGNPATENTS 4,931 Great Britain of 1905 685,204 Germany Dec. 14, 1939

